**5. Features of breeding of grape genotypes resistant to oidium in crossing of Crimean native varieties with complex interspecific hybrids**

Analysis of the laws of inheritance of resistance to oidium in hybrid progeny makes it possible to carry out scientific selection of initial forms for immunoselection programs realization. These objective laws are established on the basis of the study on a fixed infection background of representational material of hybrid populations obtained in the process of crossing of various parental forms with resistance to the pathogen. In different cross-combinations the variability of feature of oidium resistance was revealed.

A significant number of highly susceptible to oidium seedlings, up to 7%, was obtained in crossings with participation of varieties 'Sary Pandas' and 'Misgiuli Kara'. The biggest percentage rate of highly resistant seedlings (9 points) was recorded in the combination of 'Khersonesskii' x 'JS 26–205' (22%). Crossings of 'Kok Pandas' x 'Tsitronnyi Magaracha' (4.5 points), 'Kokur Chernyi' x 'Ifigenia' (4.3 points), 'Misket' x 'Ifigenia' (4.3 points), 'Muscat Jim' x 'Kokur Belyi' (4.5 points) mostly followed to the formation of medium-resistant to oidium forms. It should be noted that the average score of resistance to oidium in all populations was higher than in the initial Crimean native varieties.

The breeding value shows the possibility of distinction of highly-resistant, resistant and medium-resistant to oidium plants in hybrid population in the contrast to the sensitive Crimean native varieties. It was determined as the


*Biological Characteristics of Native Grape Cultivars of Crimean Region and Availability… DOI: http://dx.doi.org/10.5772/intechopen.98975*

#### **Table 11.**

*Breeding characteristics of hybrid populations by oidium resistance.*

percentage of seedlings in populations with 5, 7 and 9 points of oidium resistance. Cross-combinations (**Table 11**) involving complex interspecific hybrids of varieties 'Muscat Jim', 'Spartanets Magaracha' and 'Magarach No. 31-77-10' had the highest breeding value. The most effective was the combination of 'Muscat Jim' x 'Shabash' with the yield of resistant and highly-resistant seedlings 10.7 percent. Degree of the dominance reflects the contribution of parent components to the variability of the trait. Negative values of the degree of dominance show that the deviation of the traits of resistance to oidium goes to the direction of more susceptible parental form. The degree of dominance shows that in 'Tashly' x 'Krymchanin' there is a hybrid depression, in the population of 'Kokur Chernyi' x 'Ifigeniya', 'Misket' x 'Ifigenia', 'Kok Pandas' x 'Tsitronnyi Magaracha', 'Khersonesskii' x 'JS 26–205' - there is a deviation to a more susceptible parent. In populations 'Kok Pandas' x 'Spartanets Magaracha', 'Muscat Jim' x 'Shabash', 'Kefesiya' x 'Spartanets Magaracha', 'Sary Pandas' x 'Spartanets Magaracha' - there is a slight dominance of more stable parent. Only in one population 'Magarach No. 31–77-10' x 'Gevat Kara' (2.19%) there was a deviation to a more stable parental form.

In populations with the participation of Crimean native varieties 'Misgiuli Kara', 'Sary Pandas', 'Kefesiya', 'Shabash', 'Kok Pandas', 'Gevat Kara' and 'Magarach No. 31-77-10' x 'Gevat Kara', hypothetic heterosis from 1.9 to 36.5 percent was noted. The transgressive recombinants were not observed in the studied combinations.

One of the main parameters characterizing the genetic potential of parental forms is the hereditability of breeding traits. The effectiveness of breeding selection in the studied populations is characterized by the parameter of hereditability of the trait, which is determined by the method of dispersion analysis of single-factor complexes. To calculate the hereditability indices, 13 single-factor complexes, including from 2 to 6 cross-combinations, were organized (**Table 12**). The lowest


#### **Table 12.**

*Dispersive parameter of inheritance of resistance to oidium.*

average score of 3.7 by the complex trait of resistance to oidium of Crimean native female forms possessed combinations of 'Kefesiya' and 'Misgiuli Kara' varieties, the highest - 'Kokur Chernyi' variety (4.2%), but the data presented for the last variety was not reliable (0.1). Inaccuracy did not indicate the absence of the influence of parents on genetic diversity of the progeny, but was explained by the limited number of seedlings in populations and small number of cross-combinations in some single-factor complexes. Average values of the remaining female forms did not exceed 4 points, and ranged in 3.8 points for 'Sary Pandas' variety and 3.9 points for 'Kok Pandas'. In crossbreeding complexes with Crimean natives, where interspecific varieties 'Muscat Jim' and 'Magarach No. 31-77-10' were used as female forms, the resistance to oidium was 4.2 and 4.1 points respectively. The highest resistance among the complexes of male forms was observed in the variety 'Spartanets Magaracha'.

For female varieties strength of the influence (0.1) of interspecific varieties 'Muscat Jim' and 'Magarach No. 31-77-10' on the inheritance of resistance to oidium of the progeny in crossing with Crimean natives is reliably confirmed. Values of this parameter, 4.3 and 2.5, indicate that usage of these varieties as female forms in crossing with Crimean native varieties will make it possible to obtain stable seedlings in F1 depending on the specific combining ability of the parental components. The dispersion complexes of the Crimean natives 'Sary Pandas', 'Kok Pandas', 'Migiuli Kara', 'Kefesiya' and 'Kokur Chernyi' are characterized by zero influence on the progeny's resistance to oidium, as confirmed by parameters of reliability. The use of these varieties as parental forms with various donors of resistance to oidium will not allow to obtain a significant number of resistant genotypes in F1.

*Biological Characteristics of Native Grape Cultivars of Crimean Region and Availability… DOI: http://dx.doi.org/10.5772/intechopen.98975*

It is established reliably that high proportion of genotypically determined inheritance of the trait of resistance to oidium is observed in crossing with male forms of interspecific origin 'Spartanets Magaracha', 'Tsitronnyi Magaracha'. In other words, these donors of oidium resistance, regardless the stability of another parental component, provide a high yield of oidium resistant forms in hybrid populations. Local varieties of Crimea 'Gevat Kara', 'Shabash' and 'Kokur Belyi' do not affect the oidium resistance of their progeny.
